Radio receiving- system



i KPSiU? SR 1343735535 f F i R. H. MARRIOTT- RADIO RECEIVINGSYSTEM. 3/ v f APPLICATION mg 0E ;.26, ms.

' 7,2 Patented Feb. 21, 1922.

2 SHEETS-SHEET 1.

R. H. MARRIOTT.

RADIO HECEWING SYSTEM.

APPLlCATION FILED nmzs, ms.

1,407,205 Patented Feb. 21, 1922.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

RADIO RECEIVING SYSTEM.

Specification of Letters Patent.

Patented Feb. 21, 1922.

Application filed December 26, 1916. Serial No. 138,728.

To all whom it may concern:

Be it known that 1, ROBERT H. MARRIOTT, a citizen of the United States, and resident of Bremerton, county of Kitsap, and State of Washington, have invented certain new and useful Improvements in Radio Receiving Systems, of which the following 1s a specification.

This invention relates to a method of and apparatus for treating disturbing electric forces which have a capacity for produc1ng violent, impulse or surge producmg effects, so as to' neutralize or cut out such effects before they reach instruments upon which their action might be detrimental and to do this in such a way that other electric currents of a more sustained or periodic character will not be seriously interfered with in their transmission to and action upon the same instruments.

It is the object of this invention to cause the undesirable currents, the effects of which it is desired to dissipate or neutralize, to produce two currents of definite but different periods, then to transform one of these currents into a current of the same period as the other and then, by combining these two currents after they have been made of the same period, cause both to be neutralized, thus leaving only the effects produced by the periodic current which it is desired to transmit.

The features of novelty in my invention will be hereinafter described andthen specifically set forth in the claims.

In the accompanying drawings I have shown diagrammatically certain constructions and arrangements of parts forming radio receiving systems in which my invention has been incorporated, the same representing the arrangements and combinations of parts which are well adapted for illustrating the principles involved in my invention.

Figure 1 represents a system in which my invention has been applied to a single antenna.

Figure 2 is a plan view of an antenna.

Figure 3 represents a system in which two antennae are employed, so connected with other parts that the objectionable efi'ects produced in one circuit are counteracted by the like effects in the other.

Figure 4 is a double antenna system designed for the neutralization of audio frequency disturbances.

Figure 5 represents a method of neutral- 1z1ng audio frequencies due to atmospherics set up 1n a radio receiver or amplifier.

Figure 6 is similar to Figure 5, but illustratingthe use of a specific type of rectifier. Th1s invention is particularly well adapted for use in radio signaling, to neutralize the dlsturbing effects produced by electric discharges or pulsations, such for instance as are commonly referred to as static, by interruptions produced in power currents, as by opemng and closing switches, and by variations of any kind, whether produced accidentally or by design in electric currents wh ch may be capable of producing surges or lmpulsive action on the receiving circuit, yet it is not limited to this particular field of use but is also applicable to the control of currents of much greater strength and power, irrespective of the use to which they may be applied. It may be applied to the control of power transmission lines and their protection against surges set up therein from any cause. 'I will more particularly describe the application of my invention to radio telegraphy, as that is a field wherein it is at present more particularly applicable.

Referring to Figure 1, the device, represented as a whole by the character 1, represents an antenna and is of rectangular outl1ne, consisting of an upper section 11, vertical sections 12 and 14, and bottom section 13, the latter being shown .as grounded. This also includes one coil 15 of a coupler 15, 16, through which the impulses are transferred to the receiving or translating mechanisms.

In the associated or receiving circuit 2 which contains the other coil 16 of the coupler, 20 represents a detector 21 and 22 condensers, and 3, a translating mechanism, here shown as a telephone.

Considering Figure 1, a direct discharge of a disturbing or violently shocking character to the upper arm 11 of the antenna at point X flows in approximately equal quantities in opposite directions producing minimum excitation of the antenna circuit at the period to which the antenna and receiving circuits are adjusted, thereby minimizing the effect of the direct discharge to the antenna so far as concerns the receiving of radio messages sent on wave lengths corresponding to the period of said circuits.

The top wire 11 of the antenna circuit of Figure 1 is indicated by the line 11 in Figure 2. Electromagnetic waves produced by more or less distant discharges in direction N or S from the antenna of Figure 2, tend to produce currents in opposite directions from X through both branches 12 and 14 to earth, thereby minimizing the excitation of the antenna in the period to which it is adjusted for radio messages.

More or less distant discharges occurring in the general direction W and E from the antenna 11 tend to produce more or less opposing currents in the antenna to earth but they also excite the antenna radio signal circuit 1, as shown in Figure 1, producing current of the radio signal frequency to which it is adjusted. Up to this point disturbances from direct discharge, from distant discharges in directions N and S and, a portion of those from direction WV and E have been neutralized, still leaving at times an objectionable remainder in the form of radio frequency alternating current flowing in the antenna circuit at the period to which this circuit is adjusted.

The decrement of this remaining current is dependent on the constants of the antenna radio signal circuit, and is therefore more or less similar in radio frequency and decrement to the radio frequency and decrement of the signals from a spark station. However, the irregular group frequency or spacing of the current trains due to the atmospheric discharges, difiers from the nearly regular group frequency due to the spark transmitters, or the note produced by beat receivers from constant amplitude transmitter signals. The radio transmitters and receivers produce regular frequencies which can be more or less tuned to, while the atmospherics produce effects that tend to shock a resonant device, whatever be the period to which it is adjusted.

In times of more severe atmospherics the neutralizing and diminishin of effects described above may not be sufiicient but may require still further neutralization to assure practical radio receiving.

To neutralize the remaining effect of the atmospheric discharges, a second similar antenna 10 of Figure 3 may be used, preferably in the same vertical plane as the first antenna, 1, and as indicated diagrammatically in Figure 3. The second antenna 10 is adjusted for one half the frequency or twice the wave length of antenna 1. This second antenna operates like the first, leaving a residue in the form of current excited in it by the atmospherics at the period to which it is adjusted. However, this second antenna being of half the frequency of the first, is too far out of tune to be materially affected by signals to which the first antenna is adjusted. By coupling the rectifying circuit 40, 45, 44 and 43, and circuit 40, 45, 46, 41 and42 and by coupling inductances 42 and 43 with inductance 47, as diagrammatically shown in Figure 3, wherein rectifiers 41 and 44 cause the successive half waves to flow through inductance 42 and 43 in the same direction relative to 47, the frequency set up in 47 is made to be twice the frequency of the current in antenna 10. The circuit which includes inductances 47, 48 and condenser 49, is adjusted for the same frequency as that produced in inductance 47 and is coupled through the circuit which contains inductances 16 and 17 with antenna 1, so that the current induced in 48 from inductance 17 is of a like frequency and in opposite phase to that induced in 47 from 42 and 43. This neutralizes the currents set up by atmospherics; however, as practically no current is set up in antenna 10 by the signal impulses to the frequency of which antenna 1 is tuned, there is practically no neutralizing signal current set up} in the circuit containing 47, 48 and 49, and the signal therefore affects detector 20 to render the signal audible in telephone receiver 23 through the usual functioning of detectors 20 and condenser 21.

A diagram to illustrate neutralization in the audio-frequency circuit is shown in Fig-- ure 4. In this two antenna: 1 and 10 as heretofore described are shown. Antenna 1 is coupled through inductances 15, 16 with circuit 5 which contains condenser 25, both these circuits being adjusted to the frequency of the radio signal, while antenna 10 and circuit 50 are adjusted to another frequency such that practically no current will be set up in them by a radio signal which acts upon antenna 1.

The circuits 240 and 241 which contain detectors 200 and 201 in the two portions of the receiving system, are adjusted so that the audio frequency currents due to atmospherics and similar objectionable discharges, set up in the circuits containing condenser 27 and inductance 300 and that containing 28 and 29, are practically alike. 29 and 300 are opposing primaries coupled to the secondary 310 on the iron core 320.

The audio frequency currents due to the atmospherics, produce neutralizing magnetic fields in secondary 310, while the radio signal currents due to the received radio signal, are practically only set up in antenna 1, so that the audio frequency currents due to the radio signal are set up in circuit 27, 300, and transferred to the telephone receiver 23 without material neutralization.

This neutralizing in circuits subsequent to the antenna circuit can be used in conjunction with other forms of antenna but, other things being equal, as much neutralization as is practicable in the antenna circuit is desirable because, if strong currents exist in the antenna, sufficient current is 7 give practically equal energy effect in infrequently induced in the subsequent cirthe signal frequency in inductance 33 and cuits to render rectifiers and detectors temone half the signal frequency in inductances porarily inoperative, or cause them to func- 31 and 32, or greater energy in 31 and 32 tion in some unsatisfactory manner. for elimination by dissipation or neutral- Where it is impractical to maintain two ization. antenna for use in neutralization, circuits as Windings 31 and 36 being on the same schematically shown in Figure 5, may be transformer core 35, and windings 32 and used. In this, inductive windings, 6, 7 are 37 on a similar core 38, and the cores being connected to the radio receiver or amplifier magnetized to the knee of the saturation 18, and adjusted to produce an aproximately curve by battery 8 through windings 80 and aperiodic circuit or a circuit having rela- 81, the current induced in the suitably contively the same shocking or impulse excitanected windings 36 and 37 is made to be tion effect on the audio frequency circuit 62 twice the frequency of the current in the and 72. Circuit 62 is adjusted to the audio windings 31 and 32 and the same as the frequency of the spark signal or the beat frequency induced from winding 33 to 83. receiver note where constant amplitude radio Windings 36, 37 and 83 are connected in the signals are being received. Circuit 72 is adsame circuit so that the currents produced justed to one half the frequency of circuit 62. therein are in opposition, whereby the cur- By means of the transformers 74, 75, 76 rents due to atmospherics and other shockand 52, 53, 54, and 55, the frequency of the ing disturbances are neutralized, while the current induced in coil 55 is brought to twice audio frequency currents produced by the that in circuit 72 and coil 74, and to the signal are not materially neutralized. same frequency as that induced in winding The truth of the action above described 58 through the transformers 64, 65, 66 and is pointed out in the following publications: 68, 69, 58. Institute of Radio Engineers, vol. 3, No. 1

secondaries 55 and 58 are connected to of 1915, Papers on Radio Frequency Changbring the currents so induced into opposite ers by Alfred N. Goldsmith; page 74. See phase in the circuit which contains the mem also German Patent No. 1497 61 to Epstein, ber 23, which is an amplifier, telephone reof 1902, and also any available description ceiver, or like instrument. of the radio frequency transformers used at The shocking and irregular currents prothe Sayville, Long Island radio station. duced by atmospherics and by the improper It is obvious that this principle of neutraloperation ofan amplifier, when used, proization may be likewise carried out by forms duce practically an equal amount, of effect in V of circuits, relative frequencies, methods of circuits 72 and 62, which effect is neutralized rectification, et cetera, other than these speas above described. While at the same time cifically described above and I do not limit audio frequency currents due to the signal myself to these particular illustrations and produce the chief effect in circuit 62 which ex lanations of the principle. circuit is tuned to that frequency. Any efat I claim as my invention is: feet of the signal which may be produced in 1. In a radio signalling device, the comcircuit 72 is rectified and its frequency bination with a plurality of receivin cir changed to twice that of the signal, which cuits susceptibmpulse excitation m1 only neutralizes the signal current to a relahaving radio frequencies, of a neutralizing tively small extent. circuit and a circuit which contains a sta- Figure 6 diagrammatically shows another t' nary aperiodic frequency changer. arrangement of circuits for neutralization of 2. In a radio signalling device, the comthe noise producing current due to atmosb1 tion with a plurality of receiving cirpherics and amplifiers. cuits susceptible to impulse excitations and 3 represents a receiver or amplifier. Cirhaving radio frequencies, of a neutralizing cuits 30, 31, 32 and 33, 34, are adjusted circuit and means for coupling said first so that with the receiver or amplifier 3 connamed circuits with said neutralizing circuit nected, they provide circuits having two comprising two intermediate circuits, one principal degrees of freedom such that the of which contains a stationary aperodic fremaximum amount of current of one half quency changer. the audio frequency of the desired signal 3. In a radio receiver, a plurality of will flow through primaries 31 and 32, which aperiodic radio frequency circuits, a neutral latter inductances are adjusted in circuit izing circuit, coupled with said circuits, one for maximum current at one half the sigof said couplings including a stationary nal frequency, and so that the impulsive aperiodic frequency changer. irregular current due to atmospherics or un- Signed at Seattle, Washington, this 16th desirable functioning of the amplifier, will day of December, 1916.

ductances 31 and 32 and produce current of ROBERT H. MARRIOTT. 

